HTML5 WebViewer Text search

Dear PDFTron team,

I am trying to set up a nicer search interface in my project. The idea would
be to display a modal when there is no search result (instead of the default alert “end of document”).
To that end, I am trying to use TextSearchInit :
https://www.pdftron.com/webviewer/demo/lib/html5/doc/symbols/CoreControls.DocumentViewer.html#TextSearchInit

The problem is that when there are no result, it seems that the callback function is not called.
So would you have an idea how to detect the absence of results in a search?

Best regards,
PY